The investigators will continue to study and describe the careers of 248 male chronic opioid users in San Antonio. The subjects were selected as research subjects when they were hospitalized for treatment of opioid dependence during the years 1964 through 1967. Retrospective and prospective data collection began in 1966; prospective data collection continues in 1979. Data are collected by periodic interviews with subjects and by review of records of law enforcement correctional, and treatment agencies. Brothers who did not use an opioid drug are interviewed. In addition, data are collected about community conditions affecting opiod use. Subjects are predominantly Mexican American. They began opioid use at the median age of 17; in 1980, if all were alive, the group would have a median age of 42. Continual prospective study should yield important information about a little known period, after the age of 40, in the career of the opioid user. The project will continue to produce information about the relation of background predictors to long-term outcomes, the consequences of multiple treatment and correctional interactions, and of the frequency of prolonged abstinence.